Most of the traditional microphones are electret microphones. For such microphones, as sounds are converted into electric signals via electret diaphragms, sound pick-up effects are poor when environmental noises are loud.
For piezoelectric microphones, as vibrations produced by sounds are converted into electric signals via piezoelectric ceramic sheets, sound pick-up effects are excellent in a noisy environment. However, existing piezoelectric microphones are complex in structure and large in size, which renders assembly inconvenient. Moreover, as their machining manners are greatly different from those of traditional electret microphones, additional devices are required to be purchased for production and machining, which increases production costs of microphone manufacturing enterprises.